Saguaro NP

This stand of saguaro cacti benefits from a combination of ideal soil and moisture conditions. It led to the creation of a National Park.

Today we attended a lecture about the Geology of the Rincon Mountains. It was presented by a volunteer who in his former life taught geology for 40 years. In about 45 minutes we couvered  courses in Geology 101 and Geology 102. We learned about Plate Tectonics, Calderas, basin and range geology, and the fact that Tucson is built on about 8,000 feet of fill.